1. Field of the Invention
The present invention relates to an RF antenna switch circuit, a high frequency antenna component, and a mobile communication device, and more particularly, to an RF antenna switch circuit including a common switch block, a high frequency antenna component, and a mobile communication device.
2. Description of the Related Art
In a highly information-oriented society, use of various mobile communication devices is being increased. These various mobile communication devices need mobility along with improvement of communication performance and thus miniaturization is also needed.
Accordingly, in high frequency components used in the mobile communication device, for example, an RF antenna, a multi-band RF antenna having an SPDT switch structure in which a transmitter and a receiver are integrated to support miniaturization is used. Particularly, this RF antenna is implemented as one chip along with the need for miniaturization.
A conventional RF antenna switch transceives a signal through one antenna by disposing a transmitting transistor on a transmitting path of a transmitting terminal and a receiving transistor on a receiving path of a receiving terminal.
At this time, in a conventional example, a plurality of transistors are disposed on the transmitting path and the receiving path to be connected in series to withstand high output power applied as input. That is, the plurality of transistors are connected to each of the transmitting path and the receiving path. When a plurality of switching devices such as transistors are connected to the transmitting path and the receiving path to withstand the inputted high output power, a size of an RF switch is increased.
Further, in a conventional SPDT switch structure, for example, when using an FET device, in on-off states of the FET, loss due to on-resistance and off-capacitance, not due to abnormal short-open circuits, occurs and isolation is reduced. At this time, since trade-off exists between insertion loss of a switching device on one path and isolation on the other path, it is necessary to improve an isolation characteristic with the other path.
Due to this, in a conventional example, in order to improve the isolation characteristic with the other path, a transmitting terminal-side shunt transistor and a receiving terminal-side shunt transistor are provided to be connected to a ground. At this time, in order to withstand high output power applied as input, the transmitting terminal-side shunt transistor and the receiving terminal-side shunt transistor form a structure in which a plurality of transistors are stacked in series. That is, the plurality of transistors are separately stacked in the respective transmitting terminal-side shunt circuit and the receiving terminal-side shunt circuit. Accordingly, the size of the RF switch is increased when designed to withstand high output power.